The fat soluble vitamins identified in Table 1 are needed for body tissue growth, maintenance, and reproduction. Therefore, the body requires a specified amount per day of each of these vitamins. Vitamins classified as water soluble are also identified in Table 1. These vitamins are generally used for metabolic purposes with the amount needed being proportional to the amount of feed or energy consumed. Feed components and intestinal microbial synthesis provide some of the B vitamins needed by the pig, but others must be added to the diet.
Storage, processing, and the contact of vitamins with certain trace minerals may lower the activity of many vitamins in the premixes, and mixed complete feeds. Some of the vitamins within the premixes are in a stabilized form that extends their shelf life. Premixes should always be stored in a cool, dry location and for a short time period. Purchasing a combination vitamin-mineral premix will result in more loss of vitamin activity than if the vitamin and mineral premixes were stored separately. Generally, a storage period not to exceed three months will be satisfactory for most vitamin premixes.